Wine is not an inert substance and it changes with age. Very few wines are enjoyable to drink when old, but there are a few that will. A potential purchaser of an old wine will want to know how drinkable the wine in the bottle is. Of course the only way to be certain is to open the bottle and taste it. Since they cannot do that before purchasing there are several indicators that they will investigate. In the business it is known as provenance. A wine’s provenance directly affects its value.